Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S43/00—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights
  • F21S43/10—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights characterised by the light source
  • F21S43/13—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights characterised by the light source characterised by the type of light source
  • F21S43/14—Light emitting diodes [LED]
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
  • B60Q1/00—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor
  • B60Q1/26—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic
  • B60Q1/2661—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic mounted on parts having other functions
  • B60Q1/2665—Arrangement of optical signalling or lighting devices, the mounting or supporting thereof or circuits therefor the devices being primarily intended to indicate the vehicle, or parts thereof, or to give signals, to other traffic mounted on parts having other functions on rear-view mirrors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R1/00—Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
  • B60R1/12—Mirror assemblies combined with other articles, e.g. clocks
  • B60R1/1207—Mirror assemblies combined with other articles, e.g. clocks with lamps; with turn indicators
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S43/00—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights
  • F21S43/30—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights characterised by reflectors
  • F21S43/31—Optical layout thereof
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
  • F21S43/00—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights
  • F21S43/40—Signalling devices specially adapted for vehicle exteriors, e.g. brake lamps, direction indicator lights or reversing lights characterised by the combination of reflectors and refractors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
  • F21Y2115/00—Light-generating elements of semiconductor light sources
  • F21Y2115/10—Light-emitting diodes [LED]

Definitions

• the present invention relates to light reflector arrangements.
• the present invention relates to a light reflector arrangement for use in a lamp for an automotive vehicle, although the invention is not limited to this application. Further, the present invention relates to a lamp assembly for an automotive vehicle.
• LEDs Light emitting diodes
• LEDs are used as light sources in many automotive lamp applications. LEDs are fast replacing traditional incandescent light bulbs since they are more energy efficient, have a longer service life and permit shallower packaging compared to most bulb-type assemblies.
• an LED is an inherently directional light source meaning that the relative luminous intensity of an LED varies with viewing angle (or direction).
• the luminous intensity is highest at 0° (normal viewing angle) and drops off significantly as the viewing angle approaches 90°.
• the effect of this directionality is that an LED appears brightest when viewed directly and becomes dimmer as the viewing angle increases.
• LEDs used in automotive lamp applications have the drawback that when active, the LEDs appear as a series of discrete "bright” or “hot” spots.
• the lamp will also be quite directional such that when viewed from an acute angle, the lamp will appear dimmer.
• optical diffuser In the past, directional light from LEDs has been diffused by an optical diffuser.
• An optical diffuser is typically some kind of translucent object that scatters light in all directions. Most diffusers however are inefficient as some light is lost to reflection and not all light passes through the diffuser. This solution, while assisting to spread the directional light to create a uniform appearance, suffers from optical inefficiencies caused by the diffusing medium. In the automotive lighting industry, optical efficiency is an important design driver as manufacturers seek to reduce cost and package size of the lamp.
• An object of the present invention is to ameliorate one or more of the above described difficulties or at least provide a useful alternative to arrangements of the type discussed above.
• the object of the invention is solved by a light reflector arrangement of claim 1.
• Preferred light reflectors of the invention are described in claims 2 to 11.
• the invention also is solved by a lamp assembly of claim 10 with preferred lamp assemblies being described in claims 11 and 12.
• a light reflector arrangement including: at least one light emitting diode (LED) light source; for each light source, the light reflector arrangement including:
• a first reflector configured to receive light from the light source and reflect said light towards a second reflector such that light reflected from the second reflector has substantially uniform luminance observable from a single direction.
• the first reflector has a non-spherical curvature.
• substantially all light emitted from the light source is incident upon the first reflector.
• the second reflector includes light scattering means consisting of either a rough surface, pillow optics or a wave form comprising a plurality of trough-shaped reflectors.
• the light reflector arrangement further includes a lens configured to receive the light reflected from the second reflector, the lens providing a viewing surface for the light reflector arrangement.
• the lens has a light diffusing surface opposite the viewing surface such that light output through the lens has a substantially uniform luminance observable from more than one direction.
• the light diffusing surface of the lens may be formed by applying a surface roughness of greater than 0.4 microns.
• the lens is tinted so as to only allow light transmission of between 30-75%.
• the tint may be black or any other suitable colour to achieve the desired light transmission.
• the first reflector and the second reflector are integrally moulded.
• a lamp assembly for an automotive vehicle including:
• the lamp assembly further including:
• a first reflector configured to receive light from the light source
• a second reflector configured to receive reflected light from the first reflector; the second reflector having light scattering means for removing directionality of light reflected from the second reflector;
• a lens configured for receiving light reflected from the second reflector, the lens having a viewing surface and a light diffusing surface opposite the viewing surface;
• light output through the lens has a substantially uniform luminance observable from more than one direction.
• the lamp assembly is a turn signal lamp housed in an exterior rear view mirror of the vehicle.
• the lamp assembly may be used for a rear tail light, rear brake light, or front position light.
• a lamp assembly for an automotive vehicle including:
• the lamp assembly further including:
• a first reflector configured to receive light from the light source
• a second reflector configured to receive reflected light from the first reflector
• the second reflector having a waveform comprising a plurality of trough-shaped reflectors for removing directionality of light reflected from the second reflector
• a tinted lens allowing light tranmission of between 30-75% configured for receiving light reflected from the second reflector, the lens having a viewing surface and a light diffusing surface opposite the viewing surface;
• light output through the lens has a substantially uniform luminance observable from more than one direction.
• Figure 1 is a perspective view of a turn signal lamp housed in an external rear view mirror of a vehicle
• Figure 2 is a perspective view of a light reflector arrangement according to an embodiment of the invention.
• Figure 3 is an exploded perspective view of a section of the light reflector arrangement of Figure 2;
• Figure 4a is a perspective view of a segment of the light reflector arrangement of Figure 2 showing the path of light rays in a single plane from the light source to the lens;
• Figure 4b is a cross-sectional view of a segment of the light reflector arrangement taken through the plane of the light rays shown in Figure 4a;
• Figure 5a is a figurative view illustrating light output from two arbitrary second reflectors of the light reflector arrangement
• Figure 5b is a figurative view of the lens of Figure 5a showing discrete segments of substantially uniform luminance observable from a single direction;
• Figure 6a is a figurative view illustrating light output from adjacent second reflectors of the light reflector arrangement where each second reflector has a wave form
• Figure 6b is a figurative view of the lens of Figure 6a showing an output of substantially uniform luminance observable from more than one direction but having stripes in the output;
• Figure 7a is a figurative view illustrating light output from adjacent second reflectors of the light reflector arrangement where each second reflector has a wave form and the lens further includes a light diffusing surface;
• Figure 7b is a figurative view of the lens of Figure 7a showing an output of substantially uniform luminance observable from more than one direction.
• the present disclosure relates to a light reflector arrangement able to provide a light output from an LED source input having substantially uniform luminous intensity.
• a light reflector arrangement able to provide a light output from an LED source input having substantially uniform luminous intensity.
• a lit surface is viewed from a distance of lm, a variation of luminous intensity of 2:1 is perceived by the human eye to be 'substantially uniform' or 'homogenous'.
• the light reflector arrangement described herein has particular usefulness in the automotive lighting industry where it may be used in vehicle lamps such as turn signal lamps, rear tail lamps, rear brake lamps, front position lamps etc.
• Figure 1 provides a perspective view of a vehicle turn signal lamp 100 housed in an external rear view mirror 10 of a vehicle.
• the external rear view mirror 10 includes a casing 20 which houses a mirror (not shown) and a turn signal lamp 100.
• the turn signal lamp 100 is integrated into the rear of the mirror casing 20.
• the observable portion of the turn signal lamp 100 is lens 110 (shown more clearly in Figures 3 -4b).
• the lens 110 may extend slightly outward from the mirror casing 20 and will generally have an elongate profile shaped to conform to the outer contour of the mirror casing 20.
• the light reflector arrangement 120 includes a plurality of LED light sources 140 mounted to a printed circuit board (PCB) 130. Each light source 140 is associated with a first reflector 122 and a second reflector 124. The respective first and second reflectors 122, 124 associated with each light source 140 are integrally moulded and arranged adjacent one another in lamp housing 22. In the arrangement shown in Figure 2, there are six first and second reflectors 122, 124 associated with six LED light sources 140. More or less light sources and reflectors may be used depending on the application, packaging restraints and efficiency requirements of the system.
• FIG. 2 Overlayed onto Figure 2 is a section of the mirror casing 20 and lens 110. Also shown schematically are light rays in a single plane emitted from one of the light sources 140 that is output through the lens 110. As shown, the light sources 140 are mounted above the viewable portion of the lens 110 behind part of the mirror casing 20 such that the light sources 140 are not directly viewable through the lens 110.
• the reflectors 122, 124 may be manufactured from a polycarbonate (PC) or other suitable substrate material.
• the reflectors 122, 124 are coated using a vacuum metallization process which provides them with a reflectivity of approximately 80%.
• the reflectors could be manufactured from a naturally reflective substrate such as white PC.
• the lens 110 may be manufactured from an acrylic (PMMA) or other suitable transparent or semi- transparent substrate, and would typically be l-3mm thick.
• Figure 3 shows an exploded view of a segment of the light reflector arrangement 120, light source 140, PCB 130 and segment of the lens 110.
• Figures 4a and 4b show views of the segment of the light reflector arrangement 120 showing the path of light rays 141, 142 in a single plane from the light source 140 to the lens 110.
• light emitted from the light source 140 is directly incident upon the first reflector 122.
• the first reflector 122 is positioned such that substantially all light emitted from the light source is incident upon and captured by the first reflector 122.
• the first reflector 122 may further have a hood 122a which helps to minimise any leakage of light from the light source 140. As light from the light source 140 is not incident directly upon the second reflector 124, efficiency of the arrangement is enhanced.
• the first reflector 122 has a complex curvature which is generally non-spherical having more than one radius of curvature.
• the second reflector 124 receives light reflected from the first reflector 122.
• the second reflector 124 is generally concave and may have a single radius of curvature.
• the surface of the second reflector 124 includes light scattering means 150 in the form of a plurality of scoop or trough portions that scatter light incident upon the second reflector 124 as will be described further.
• the first reflector 122 is configured (i.e. by position and curvature) such that light output from the surface of the second reflector 124 has a substantially uniform luminance observable from a single direction.
• the uniform light output from the surface of the second reflector 124 is achieved through optic design.
• Light from the light source 140 is mapped in power bands of varying light intensity between the first reflector 122 and second reflector 124.
• the first reflector 122 is shaped such that light reflected from each surface area of the first reflector 122 is incident upon an equal surface area of the second reflector 124 with substantially the same power level. Through this power band mapping, a uniform light output from the second reflector 124 is able to be achieved.
• the precise shape of each reflector is developed by following the above process, and will change as geometric constraints change.
• the second reflector 124 is configured to reflect light through lens 110. In this way, substantially all light reflected from the surface of the second reflector 124 is directed towards the lens 110 to maximise efficiency and minimise any leakage of light out of the system.
• the first and second reflectors 122, 124 therefore function to transform a directional LED light source 140 into a uniform or homogenous light output at the lens 110. Light reflected from the second reflector 124 is directed through lens 110 and is directly viewable by an observer. When the lens 110 is viewed normal to its surface, a homogenous band of light is viewable having substantially uniform luminous intensity.
• the reflector arrangement 120 of the present invention therefore removes "hot spots" normally associated with LED light sources used in prior art vehicle lamps with good optical efficiency.
• the above described light reflector arrangement 120 represents an embodiment of the present invention in one form. It has been found that when the second reflector 124 has a plain surface (with no light scattering means), the light output, whilst uniform, is still directional in that the output only has a substantially uniform luminance observable from a single direction (i.e. when a sgement of the lens is viewed normal to its surface). This is shown schematically in Figures 5a and 5b. Figure 5a depicts light rays 142 reflected from the surface of two of the second reflectors 124 (chosen arbitrarily for purposes of illustration) and transmitted through the lens 110.
• each segment would have a substantially uniform luminance. However, if either segment 110b or 11 Oe is viewed at an angle to its surface then the luminance would not be uniform. Furthermore, for this arrangement, light output from adjacent second reflectors 124 do not blend together. For example, light output through lens segment 110c would not be visible if the lens 110 was viewed normal to segment 110b.
• the light scattering means 150 may take the form of any suitable optic feature including a rough surface, pillow optics or a wave form as depicted in Figure 6a.
• the wave form 150 comprises a plurality of scoops or trough portions that function to spread the light output from the second reflector 124 substantially horizontally. Light rays being spread horizontally are depicted in Figure 6a as light rays 144 and 146. In this way, light is spread such that the light output through adjacent lens segments is blended together.
• the light diffusing surface 115 is a rear surface of the lens 110 that is opposite the front viewable surface of the lens 110.
• the light diffusing surface 115 may be formed by surface finishing the lens 110 with a tool so as to provide a surface roughness of greater than 0.4 microns.
• the light diffusing surface 115 diffuses light rays 148 in all directions so that when the lens 110 is viewed from multiple directions, a substantially uniform luminance will be observed.
• a further advantage of the diffusing lens surface 115 is that it helps to hide internal detail behind the lens 110.
• Another advantage of the present invention resides in its optical efficiency over the prior art. For example, due to optical inefficiency of using an optical diffuser, to achieve the same level of luminance that is output through the lens of the present invention, a much larger number of LEDs would previously have been required. Through efficient optical design, the number of LEDs required to achieve a given optical luminance output is minimised by the light reflector arrangement of the present invention. This in turn minimises manufacturing costs whilst still achieving optical performance requirements.
• the lens 110 of the light reflector arrangement 120 is tinted so as to only allow light transmission of between 20-75%.
• the tint may be dark (i.e.black) or any other suitable colour to achieve the above light transmission.
• the effect of this tinting is that when the light sources are OFF the lens 110 simply appears dark and no internal optics of the reflector arrangement are observable by an external viewer.
• the light diffusing surface of the lens may further enhance this effect.
• the lens 110 glows evenly with substantially uniform luminance from one or more directions.
• a turn signal lamp having a tinted lens When a turn signal lamp having a tinted lens is integrated into the housing of an external rear view mirror of a vehicle, if the housing is also black then the turn signal lamp will blend in with the surrounding casing and it may not be immediately apparent that a turn signal lamp is even there.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Multimedia (AREA)
• Physics & Mathematics (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Optics & Photonics (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)
• Lighting Device Outwards From Vehicle And Optical Signal (AREA)

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Citations (8)

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• 2013
  • 2013-12-20 EP EP13814149.4A patent/EP2941367B1/de active Active
  • 2013-12-20 WO PCT/EP2013/077814 patent/WO2014106599A1/en active Application Filing
• 2015
  • 2015-07-07 US US14/792,990 patent/US10006603B2/en active Active

Patent Citations (8)

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